1. Field of the Invention
The present invention relates to an organic electro luminescence (EL) device, and an electronic apparatus (in particular, a clock apparatus such as a wrist watch).
2. Description of the Related Art
An organic EL element is an autonomous light-emitting element, and comprises at least one organic light emitting layer arranged between a cathode and an anode; it can be driven by a direct current of approximately 3V, and can be manufactured to emit a wide variety of colors. The organic EL element has many advantages as a display element, such as having a faster response speed and a wider visual angle than a liquid crystal element, and is expected to be used in various ways, such as in a light source and in pixels of a display apparatus.
For example, in a wrist watch, a transparent organic EL panel having a light-emitting section comprising the organic EL element is provided on a dial (of the wrist watch), making it possible to obtain an analog time display on the dial, and a digital numerical display and the like on the organic EL panel, within the same face.
This type of organic EL element is made as follows. Firstly, a transparent thin-film (ITO thin-film) for anode is provided on a transparent glass substrate. Then, an anode (provided in a predetermined region containing a light-emitting section) of the organic EL element, terminals for the anode, terminals for the cathode, and interconnections between the anode terminals, are patterned simultaneously by photolithography and etching of the thin-film.
With the exception of the light-emitting section of the anode and the terminal sections, the surface of the glass substrate is covered by an insulating layer. Then, a hole injection layer and an organic light-emitting layer are provided on the surface of the glass substrate, excepting the terminal sections. Then, a transparent cathode comprising a predetermined metal thin-film is provided in a region on the surface of the glass substrate which includes the light-emitting section but excludes the terminal sections. Then, all sections except the cathode side terminal section are sealed with a sealant.
At the time of assembling the wrist watch, the organic EL panel and the drive circuit substrate are arranged in parallel at predetermined intervals with their corresponding terminals in alignment, and the dial is provided in parallel between them. A plate-like anisotropic conductive rubber member is provided between their peripheral sections, with the top and bottom end faces of the rubber member touching the faces of the organic EL panel and the drive circuit substrate. The conductive granules of the anisotropic conductive rubber member are dispersed at positions in the rubber member corresponding to the terminals, forming a continuous path of conductive rubber at these positions only; this continuous path connects the terminal of the organic EL panel to the terminal of the drive circuit substrate.
However, in an electronic apparatus such as a wrist watch wherein an anisotropic conductive member connects the terminal of the organic EL panel to the terminal of the drive circuit substrate, the drive voltage must be increased due to the high contact resistance between the anisotropic conductive rubber and the terminal of the organic EL panel.